Modern vehicles have bumper systems tuned for particular energy absorption during a vehicle-to-vehicle impact. However, tuning of bumper systems can be challenging due to conflicting design requirements, such as limitations on the packaging space occupied by the bumper system (i.e., energy absorber and/or bumper beam), limitations on bumper beam flexure and rear intrusion into the space behind the bumper beam, and limitations on cost, quality, dimensional consistency and consistency/predictability of the impact energy-absorbing profile during the impact stroke itself. Recently, there has been increasing concern and subsequent regulations addressing pedestrian impacts in an effort to reduce pedestrian injury during such an impact. This has added a degree of difficulty and complexity in bumper system design and in bumper system tunability.
Besides safety concerns, repair costs of a vehicle suffering an impact and meeting both governmental and insurance test standards are also factors to consider in the design of vehicle parts such as bumper systems. Generally, vehicle parts such as bumper systems are designed to meet governmental test standards, such as low speed insurance tests, where the particular vehicle components can withstand low speed impact, e.g., at speeds of 4 to 15 kilometers per hour (kph) (2.5-9 miles per hour (mph)).
As an added complexity in the current competitive automotive market, combined with recent government directives on fuel efficiency, reducing the overall weight of the bumper systems can also be a challenge for design engineers to both reduce costs as well as increase fuel efficiency.
Previously, simultaneous low-cost and low weight systems could be attained only by a compromise in performance. Accordingly, a need has arisen to provide low weight and low cost energy absorbing systems that can meet strict and at times conflicting design constraints.